Mercruiser Mag 350 MPI NO SPARK?

Serial # OM311933,
Year 2002
Boat was running fine. Started and ran up river 5 mins, sputtered, I put in Neutral, Idle bumped up to 1500 RPM, stalled. I thought I had a fuel delivery problem. Checked entire fuel sytem added new in-line filter, seperator/filter and low pressure pump.

Started engine, on-lift, ran for 2-3 mins at idle stalled. Restarted after priming system with key on/off, low pressure pump, Stalled again.

Now I can not get it to start at all. Hooked up DDT and had a code for Throttle position Sensor, replaced, still won't start. also had code for, something like " low 5 volts,???" can't remember.

Checked for sparkat distributor by disconnecting coil wire, at distributor and turning key while grounding wire, still NO spark. Checked all connections, coil, main harnesss, etc. all seem fine, replaced distributor cap and rotor, Still will NOT start. I switched out the ECM from my friends boat with same engine, still will not start.

Please, anybody have a suggestion? I am thinking bad coil. Shouldn't I be able to see a spark from coil wire going?

Re: Mercruiser Mag 350 MPI NO SPARK?

Borrow your pals ignition coil & module before replacing to eliminate i have similar problem although intermittent and changed coil/module with no change expensive guess for me

Re: Mercruiser Mag 350 MPI NO SPARK?

I have close to the same problemb with my 350 Mag Mercruise
I have changed out the IAC,Map,& water sensors
The only way my motor will start is at full throttle!
Did you check your spark with another spark plug grounded to the block?

Re: Mercruiser Mag 350 MPI NO SPARK?

I'm no mechanic and having some of the same issues. Could it be the shift interrupt switch grounding out the coil if it stays engaged?